There are a number of available automatic and semi-automatic firearms for use by military personnel and civilians. While fully automatic firearms are generally illegal for use by the civilian population, many of the components which constitute an automatic firearm are the same as those found within legal semi-automatic models. Arguably the most popular semi-automatic assault-type firearm used by civilians, particularly within the United States, is the AR-15. The AR-15 is the semi-automatic variant of the fully automatic M16 firearm used by United States military personnel. While AR-15 is a registered trademark of Colt Industries, a number of additional manufacturers manufacture clones of the AR-15 and market these clones under separate trademarks. While used throughout the specification, it is to be understood that the term AR-15 is meant to include not only those firearms manufactured by Colt Industries, but also those additional clones and any variants thereof.
The AR-15 and M16 are designed as modular firearms generally comprising a buttstock, lower receiver, upper receiver and barrel assembly configured to file .223 Remington or 5.56×45 mm NATO military ammunition. Each component is separable from one another and affords firearm owners the opportunity to customize the firearm with after-market components such as barrels of differing lengths, upper receivers designed to handle different calibers of rifle ammunition, flashlights, hand guards, grenade or flare launchers, flash or sound suppressors, grips, and front or rear sights. To operate, the lower receiver is configured to include a trigger wherein activation of the trigger causes a rifle cartridge housed within the chamber of the upper receiver to be fired out the barrel of the firearm by action of a reciprocating bolt carrier group. Internal mechanisms of the upper receiver expel the shell casing of the fired rifle cartridge from the chamber while components engaged with the magazine housed within the magazine well of the lower receiver feed a new rifle cartridge into the now-empty chamber. The buttstock mounts to the lower receiver and includes a buffer assembly and action (or recoil) spring in communication with the bolt carrier group where the spring pushes the bolt carrier group back toward the chamber in preparation of firing another rifle cartridge.
To date, most automatic and semi-automatic firearms, like the AR-15, have been configured to fire rifle cartridges only. There are, however, modifications available which convert an AR-15 firearm meeting military specifications (mil-spec) into an assault-style firearm capable of firing 9 mm ammunition, such as the 9×19 mm Parabellum cartridge. These modified firearms generally include an upper receiver modified to chamber and fire the smaller 9 mm ammunition compared to the larger rifle ammunition. The barrel, bolt carrier group and buffer spring are also modified to accommodate the smaller cartridges. To provide the 9 mm cartridges to the firearm, a number of attempts have been made to modify the AR-15 to mount a 9 mm caliber magazine with the AR-15 lower receiver. For instance, modified AR-15 lower receivers have been manufactured to receive a 9 mm magazine. However, these lower receivers do not meet military specifications. Alternatively, conversion blocks have been developed whereby the mil-spec magazine well of the AR-15 is configured to mount an adapter which in turn receives the 9 mm magazines. While these systems utilize the mil-spec AR-15 magazine well, they require fastening of the conversion block to the lower receiver thereby increasing complexity and build times.
As such, there is a need for a 9 mm magazine adapter which is configured to mount within a magazine well of a lower receiver meeting military specifications, such as that of an M-16 or AR-15, without requiring the disassembly of the firearm or the use of additional tools. The present invention addresses these and other needs.